Background
Safe and accessible drinking water (potable water) is important for health and must be supplied to all employees at mining operations in Western Australia.
The Department has recently been investigating contamination of water supplies with process water or microbial pathogens that have the potential to cause serious and disabling conditions. Such conditions can lead to severe, debilitating diseases that may cause death in susceptible people
Summary of hazard
Following a contamination incident, the severity of outcomes is dependent on toxicity of the chemical(s) or the ability of microbiological contaminants to cause disease, their concentration(s) in the water, the dose, and individual worker susceptibility to the contaminant.
Common symptoms of contaminated drinking water include, diarrhoea, vomiting, abdominal cramping, loss of appetite, fever, fatigue, joint pain, dark urine and skin irritations or yellowing of the skin. A person may experience one or more of these symptoms with mild to severe effects. Water-borne diseases have the potential to be very serious and include cholera, typhoid, dysentery, hepatitis A, botulism, and parasitic infections – giardiosis, cryptosporidiosis and cyclosporosis. Many of these diseases are highly contagious and can be easily transferred by person-to-person contact, eating food handled by a person with the disease or further consumption of contaminated water.
Contributory factors
Contamination of reticulated drinking water systems can occur from:
- animal defecation in or near the drinking water source
- contaminating materials (chemicals, faeces, decomposing animals) in or near damaged pipes
- infrastructure failures:
- system-derived back pressure, such as when pumps are switched on and off
- faulty plumbing or cross-connection of sewage or process water lines with the reticulated drinking water supply
- poorly designed or modified water reticulation systems resulting in “dead legs”
- elevated temperatures that promote bacterial growth, or lack of treated water at the supply point
- soiled water system components (tanks, pipework, taps) with slime and algae build-up that supports growth of pathogens
- faulty, inadequate or no disinfection treatment installed in the system (examples include filters, chlorine dosing equipment, ultra-violet sterilisation units, or ozone)
- incorrect or inadequate labelling of supply points
- persons not competent to design, install and maintain drinking water systems.